School nurses need to demonstrate that their practice is based on the best evidence available, which is usually data obtained from research. Evidence-based practice involves combining the best evidence available with nursing expertise and patient and family preferences to determine optimum care. Evidence-based practice guidelines are developed by carefully reviewing the available evidence on a topic and synthesizing this information into recommendations for practice. This article defines "evidence-based practice" and "best evidence", describes the development of evidence-based practice guidelines, discusses factors that affect the use of research and evidence-based practice guidelines in school nursing, and reviews current sources of evidence-based practice guidelines for school nurses. Strategies that school nurses can use to incorporate evidence into their practice are discussed. One recommendation is that school nurses partner with nurse leaders and nurse researchers to develop evidence-based practice guidelines relevant to school nurse practice. (Contains 5 tables.)